Recently, processing and distributing multimedia content created by other people into a new form through high speed Internet environment is becoming prevalent. However, the digital rights management (DRM) system for protecting the rights of the original author overly restricts the processing and reusing of digital content into various other formats by end users. Such a DRM system does not consider contributions made by secondary authors in modifying the content created by the original author. This obstructs potential contributions to be made by secondary authors and distribution activities of the content created by the original author.
Although, conventional DRM systems provide functions for protecting copyrights of a service provider (or a content provider), but they do not provide a function for protecting the copyright of general users who subsequently modified the contents created by the original author. Namely, conventional DRM systems do not provide a method of providing transferable rights (rights transferred from the original author which can be used within the scope of the rights of the original author by secondary authors), or a method of indicating the rights to the portion of content modified and contributed by secondary authors.
Also, conventional DRM systems send rights information separate from the content to user terminals. However, they do not provide a method which can prevent the rights information from being changed. That is, if digital content with removed rights information is distributed, it is almost impossible to trace the digital content. Although, DRM systems provide some security measures in that metadata having indicated with information related to encrypted digital content is provided, there are no particular security measures provided at the terminal environment where digital content is played.